Oleg Shpynov

This happened during parallel update - one by crontab schedule, and another process - manual update. We should avoid parallel updates on the system level with some lock file.

Discussion.

"Open in " action opens external DB in same tab for now.

Or use fuzzy search instead.

See paper Mapping Change in large networks https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0008694&type=printable

@ctrltz is it possible to use `np.log1p` to avoid this problem?

Also tokens_freqs_norm may be zero. What is correct fix for this?